Powder that is to be tabletted as a general rule does not have the flowing characteristics that is wanted but are cohesive and thus it is common that the powder is converted into a granulate prior to tabletting.
At the production of the granulate, the powder is provided with a solvent, optionally containing a binding agent so as to form a semi moist mass, which is then formed into agglomerates and is dried to granules, or if a suitable size of the agglomerate is obtained directly, is immediately dried to a suitable particle size which varies dependent on the intended use. Optionally, the granulate has to be crushed to obtain the right particle size and particle size distribution. The size may vary from some 100 .mu.m to 1.5 mm in diameter.
All products are, however, not suited for a treatment using a solvent and often an inert carrier has to be added to obtain a suitable granulate.
One way of obtaining a solvent-free granulate is to add another powder having good binding properties, to compress the pulverulent mixture into tablets or briquettes and then to crush these into a suitable particle/granulate size.
It has also for several reasons, such as a desire to get rid of unnecessary additions, been desirable to obtain highly concentrated products, and others, have raised demands for pure granulates, i.e. granulates which contain the desired substance/product, only, or at least contain essentially, i.e., 80-100% of the product desired.